What Does P071F Mean?
The transmission mode switch B circuit is reporting a high voltage condition. The signal is open, shorted to reference/battery voltage, or the switch has failed in a high-resistance state. The TCM interprets this as an invalid mode selection, and the driver may be unable to change driving modes.
Common Causes
30%
Open circuit in the mode switch B signal wire or disconnected plug
30%
Mode switch B failed open or in a high-resistance state
20%
Signal wire shorted to battery or reference voltage
10%
Open ground circuit preventing the switch from pulling the signal down
10%
TCM connector issue at the B switch input
Diagnostic Steps
1
Check the mode switch B voltage PID in live data. A reading pegged at reference voltage (5V) or battery voltage in all positions confirms a high circuit fault.
2
Disconnect the switch connector and jumper the signal to ground. If the scan tool reading changes, the wiring is OK and the switch is at fault.
3
Inspect the connector for backed-out pins, corrosion, or broken wires that could create an open circuit.
4
Measure continuity from the switch signal pin to the TCM connector pin. An open circuit confirms a wiring break that needs repair.
5
Check the switch ground circuit — an open ground forces the signal voltage high on most resistive divider circuits.
Estimated Repair Cost
$50 - $300
Parts + labor, varies by vehicle and location
The transmission mode switch B circuit is reporting a high voltage condition. The signal is open, shorted to reference/battery voltage, or the switch has failed in a high-resistance state. The TCM interprets this as an invalid mode selection, and the driver may be unable to change driving modes.
The most common cause of P071F (Transmission Mode Switch "B" Circuit High) is: Open circuit in the mode switch B signal wire or disconnected plug
Typical repair costs for P071F range from $50 to $300, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive. The transmission operates normally in its default mode. Loss of mode switch B functionality is a convenience issue. Repair when convenient.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P071F to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission
Difficulty
Type
Generic (SAE)
Recommended Tools
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